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  • 1
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    Soluble and colloidal iron in the oligotrophic North Atlantic and North Pacific (2001)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2001-08-04
    Description: In the oligotrophic North Atlantic and North Pacific, ultrafiltration studies show that concentrations of soluble iron and soluble iron-binding organic ligands are much lower than previously presumed "dissolved" concentrations, which were operationally defined as that passing through a 0.4-micrometer pore filter. Our studies indicate that substantial portions of the previously presumed "dissolved" iron (and probably also iron-binding ligands) are present in colloidal size range. The soluble iron and iron-binding organic ligands are depleted at the surface and enriched at depth, similar to distributions of major nutrients. By contrast, colloidal iron shows a maximum at the surface and a minimum in the upper nutricline. Our results suggest that "dissolved" iron may be less bioavailable to phytoplankton than previously thought and that iron removal through colloid aggregation and settling should be considered in models of the oceanic iron cycle.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wu, J -- Boyle, E -- Sunda, W -- Wen, L S -- New York, N.Y. -- Science. 2001 Aug 3;293(5531):847-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. jingfeng@mit.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/11486084" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 2
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    Phosphate depletion in the western North Atlantic Ocean (2000)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2000-08-05
    Description: Surface waters of the subtropical Sargasso Sea contain dissolved inorganic phosphate (DIP) concentrations of 0.2 to 1.0 nanomolar, which are sufficiently low to result in phosphorus control of primary production. The DIP concentrations in this area (which receives high inputs of iron-rich dust from arid regions of North Africa) are one to two orders of magnitude lower than surface levels in the North Pacific (where eolian iron inputs are much lower and water column denitrification is much more substantial). These data indicate a severe relative phosphorus depletion in the Atlantic. We hypothesize that nitrogen versus phosphorus limitation of primary production in the present-day ocean may be closely linked to iron supply through control of dinitrogen (N2) fixation, an iron-intensive metabolic process. Although the oceanic phosphorus inventory may set the upper limit for the total amount of organic matter produced in the ocean over geological time scales, at any instant in geological time, oceanic primary production may fall below this limit because of a persistent insufficient iron supply. By controlling N2 fixation, iron may control not only nitrogen versus phosphorus limitation but also carbon fixation and export stoichiometry and hence biological sequestration of atmospheric carbon dioxide.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wu, J -- Sunda, W -- Boyle, E A -- Karl, D M -- New York, N.Y. -- Science. 2000 Aug 4;289(5480):759-62.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/10926534" target="_blank"〉PubMed〈/a〉
    Keywords: Atlantic Ocean ; Cyanobacteria/*metabolism ; Iron/analysis/metabolism ; Nitrates/analysis/metabolism ; Nitrites/analysis/metabolism ; *Nitrogen Fixation ; Pacific Ocean ; Phosphates/*metabolism ; Seawater/*chemistry/microbiology
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 3
    Electronic Resource
    Electronic Resource
    Toxicity of cupric lon to eggs of the spot Leiostomus xanthurus and the Atlantic silverside Menidia menidia (1979)
    Springer
    Marine biology 50 (1979), S. 121-126 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Experiments were conducted to determine the toxicity of free cupric ion to the eggs of two marine fish: the spot Leiostomus xanthurus, and the Atlantic silverside Menidia menidia. A cupric ion buffer consisting of 5 mM of the chelator, trishydroxymethylamino methane (Tris), and varied concentrations of CuSO4 was employed to achieve stable cupric ion activities in experimental seawater media. Egg hatch of the silverside appears to be more sensitive to cupric ion than that of the spot. The silverside had 60% inhibition of hatch at a pCu (negative logarithum of cupric ion activity) of 9.4 with complete supporession of hatching at pCu values below 8.2, while the spot had 50% inhibition at a pCu of 9.0 and complete suppression at a pCu of 8.0. Cupric ion was most toxic to the eggs of silverside at or around the time of hatching, whereas a pronounced sensitivity at hatching was not apparent with the eggs of spot. Calculated estimates of the range of cupric ion activity in seawater indicate that natural activity levels may in some instances inhibit the hatching of silverside and spot eggs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00397816
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  • 4
    Electronic Resource
    Electronic Resource
    Bioavailability of dissolved copper to the American oyster Crassostrea virginica. I. Importance of chemical speciation (1982)
    Springer
    Marine biology 66 (1982), S. 77-82 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effect of complexation on the accumulation of dissolved copper by the American oyster Crassostrea virginica was determined in chemically defined exposure media. The speciation of copper was varied by varying the concentrations of total copper and model chelator, nitrilotriacetic acid (NTA). Accumulation of copper in 14-d experiments was related to the cupric ion activity and not the concentration of chelated copper. Rapid accumulation of copper occurred at cupric ion activities above 10-10 M and there was no measurable accumulation at 10-11 M.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00397257
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  • 5
    Electronic Resource
    Electronic Resource
    Relative contributions of food and water in the accumulation of zinc by two species of marine fish (1984)
    Springer
    Marine biology 80 (1984), S. 273-279 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A model food chain, utilizing 65Zn-labeled and nonlabeled food organisms, was used to measure the relative contributions of food and water to Zn accumulation by Gambusia affinis and Leiostomus xanthurus. Chlamydomonas sp. was fed to Artemia sp. which in turn was fed to G. affinis and L. xanthurus. A trace metal-chelate buffer system was used to maintain a stable free Zn ion activity (10-8.5 mol l-1) in the experimental seawater. Food represented 78 to 82% of total accumulation of 65Zn by the fish. Thus, food cannot be ignored in assessing the accumulation and toxicity of trace metals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00392822
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  • 6
    Electronic Resource
    Electronic Resource
    Effects of cupric and zinc ion activities on the survival and reproduction of marine copepods (1987)
    Springer
    Marine biology 94 (1987), S. 203-210 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The toxicity of copper and zinc to the estuarine copepod Acartia tonsa and to the two diatom food species Thalassiosira pseudonana and T. weissflogii was measured in nitrilotriacetate-trace metal ion buffer systems at 25‰ S. Overall, A. tonsa appeared to be more sensitive to cupric and zinc ion activity than either of the diatoms; however, its sensitivity varied among the different life stages examined. Adult survival was not affected within the zinc ion activity range 10-11 to 10-8 M and cupric ion activity range 10-13 to 10-11 M over a 96-h period, but a cupric ion activity of 10-10 M caused total mortality of adults within 72 h. Egg-laying rate was most sensitive to zinc, and was reduced at zinc ion activities ≧10-10 M. Naupliar survival after 96 h was reduced by zinc ion activities ≧10-8 M and by cupric ion activities ≧10-11 M, and was reduced to zero at a zinc ion activity of 10-7 M and at a cupric ion activity of 10-10.5 M. In an interspecies comparison of 96-h adult survival, Centropages typicus was more sensitive to copper and zinc than A. tonsa and the survival of Labidocera aestiva was dependent on the ratio of cupric to zinc ion activity. A comparison of our results with estimates of zinc and cupric ion activities in estuaries suggests that ionic activities of these metals are high enough in some polluted estuaries to affect the survival and reproduction of copepods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00392932
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  • 7
    Electronic Resource
    Electronic Resource
    An antioxidant function for DMSP and DMS in marine algae (2002)
    [s.l.] : Macmillian Magazines Ltd.
    Nature 418 (2002), S. 317-320 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The algal osmolyte dimethylsulphoniopropionate (DMSP) and its enzymatic cleavage product dimethylsulphide (DMS) contribute significantly to the global sulphur cycle, yet their physiological functions are uncertain. Here we report results that, together with those in the literature, show that ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/nature00851
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  • 8
    Electronic Resource
    Electronic Resource
    Photoreduction of manganese oxides in seawater and its geochemical and biological implications (1983)
    [s.l.] : Nature Publishing Group
    Nature 301 (1983), S. 234-236 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Reduction of manganese oxide was investigated by measuring the dissolution of 54Mn oxides prepared from 54MnCl2 by permanganate oxidation13: oxides prepared by this procedure13 have an approximate composition of MnO^g. Such mixed oxidation state oxides (referred to here as MnOx) are characteristic ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/301234a0
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  • 9
    Electronic Resource
    Electronic Resource
    Effects of copper and zinc on two planktonic ciliates (1986)
    Springer
    Marine biology 92 (1986), S. 21-29 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The interactive effects of copper and zinc on two estuarine planktonic ciliates, Favella sp. and Balanion sp., were determined in seawater media in which the free metal ion activities were controlled by nitrilotriacetic acid (NTA) trace metal ion buffer systems. Cupric ion activities of 10-10 M caused abnormal motility in both ciliates in shortterm (5 h) tests, and cupric ion activities as low as 10-12.8 M decreased the growth rates of both species in longer-term experiments. In the short-term tests, zinc ion activity by itself did not affect the motility of the ciliates, but there were significant interactions between copper and zinc. In the longer-term experiments, the growth of Favella sp. was optimal at the lowest cupric ion activity (10-13 M) and the two lowest zinc ion activities (10-12 and 10-13 M) and the two lowest zinc ion activities (10-12 and 10-11 M), and copper and zinc inhibited growth at activities above these values. By contrast, optimal growth rate of Balanion sp. occurred at the highest zinc ion activity (10-10 M) and the lowest cupric ion activities (10-13 to 10-12 M) and growth rate was reduced at zinc ion activities ≦10-11 M. There was an antagonism between copper and zinc which was particularly pronounced in Balanion sp.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00392741
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  • 10
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    Osmotic stress does not trigger brevetoxin production in the dinoflagellate Karenia brevis (2013)
    National Academy of Sciences
    Details
    Publication Date: 2013-06-10
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
    Published by National Academy of Sciences
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